+++ /dev/null
-/*
- * cdev.c - Application interfacing module for character devices
- *
- * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * This file is licensed under GPLv2.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/fs.h>
-#include <linux/slab.h>
-#include <linux/device.h>
-#include <linux/cdev.h>
-#include <linux/poll.h>
-#include <linux/kfifo.h>
-#include <linux/uaccess.h>
-#include <linux/idr.h>
-#include "mostcore.h"
-
-static dev_t aim_devno;
-static struct class *aim_class;
-static struct ida minor_id;
-static unsigned int major;
-static struct most_aim cdev_aim;
-
-struct aim_channel {
- wait_queue_head_t wq;
- spinlock_t unlink; /* synchronization lock to unlink channels */
- struct cdev cdev;
- struct device *dev;
- struct mutex io_mutex;
- struct most_interface *iface;
- struct most_channel_config *cfg;
- unsigned int channel_id;
- dev_t devno;
- size_t mbo_offs;
- DECLARE_KFIFO_PTR(fifo, typeof(struct mbo *));
- int access_ref;
- struct list_head list;
-};
-
-#define to_channel(d) container_of(d, struct aim_channel, cdev)
-static struct list_head channel_list;
-static spinlock_t ch_list_lock;
-
-static inline bool ch_has_mbo(struct aim_channel *c)
-{
- return channel_has_mbo(c->iface, c->channel_id, &cdev_aim) > 0;
-}
-
-static inline bool ch_get_mbo(struct aim_channel *c, struct mbo **mbo)
-{
- *mbo = most_get_mbo(c->iface, c->channel_id, &cdev_aim);
- return *mbo;
-}
-
-static struct aim_channel *get_channel(struct most_interface *iface, int id)
-{
- struct aim_channel *c, *tmp;
- unsigned long flags;
- int found_channel = 0;
-
- spin_lock_irqsave(&ch_list_lock, flags);
- list_for_each_entry_safe(c, tmp, &channel_list, list) {
- if ((c->iface == iface) && (c->channel_id == id)) {
- found_channel = 1;
- break;
- }
- }
- spin_unlock_irqrestore(&ch_list_lock, flags);
- if (!found_channel)
- return NULL;
- return c;
-}
-
-static void stop_channel(struct aim_channel *c)
-{
- struct mbo *mbo;
-
- while (kfifo_out((struct kfifo *)&c->fifo, &mbo, 1))
- most_put_mbo(mbo);
- most_stop_channel(c->iface, c->channel_id, &cdev_aim);
-}
-
-static void destroy_cdev(struct aim_channel *c)
-{
- unsigned long flags;
-
- device_destroy(aim_class, c->devno);
- cdev_del(&c->cdev);
- kfifo_free(&c->fifo);
- spin_lock_irqsave(&ch_list_lock, flags);
- list_del(&c->list);
- spin_unlock_irqrestore(&ch_list_lock, flags);
- ida_simple_remove(&minor_id, MINOR(c->devno));
-}
-
-/**
- * aim_open - implements the syscall to open the device
- * @inode: inode pointer
- * @filp: file pointer
- *
- * This stores the channel pointer in the private data field of
- * the file structure and activates the channel within the core.
- */
-static int aim_open(struct inode *inode, struct file *filp)
-{
- struct aim_channel *c;
- int ret;
-
- c = to_channel(inode->i_cdev);
- filp->private_data = c;
-
- if (((c->cfg->direction == MOST_CH_RX) &&
- ((filp->f_flags & O_ACCMODE) != O_RDONLY)) ||
- ((c->cfg->direction == MOST_CH_TX) &&
- ((filp->f_flags & O_ACCMODE) != O_WRONLY))) {
- pr_info("WARN: Access flags mismatch\n");
- return -EACCES;
- }
-
- mutex_lock(&c->io_mutex);
- if (!c->dev) {
- pr_info("WARN: Device is destroyed\n");
- mutex_unlock(&c->io_mutex);
- return -EBUSY;
- }
-
- if (c->access_ref) {
- pr_info("WARN: Device is busy\n");
- mutex_unlock(&c->io_mutex);
- return -EBUSY;
- }
-
- c->mbo_offs = 0;
- ret = most_start_channel(c->iface, c->channel_id, &cdev_aim);
- if (!ret)
- c->access_ref = 1;
- mutex_unlock(&c->io_mutex);
- return ret;
-}
-
-/**
- * aim_close - implements the syscall to close the device
- * @inode: inode pointer
- * @filp: file pointer
- *
- * This stops the channel within the core.
- */
-static int aim_close(struct inode *inode, struct file *filp)
-{
- struct aim_channel *c = to_channel(inode->i_cdev);
-
- mutex_lock(&c->io_mutex);
- spin_lock(&c->unlink);
- c->access_ref = 0;
- spin_unlock(&c->unlink);
- if (c->dev) {
- stop_channel(c);
- mutex_unlock(&c->io_mutex);
- } else {
- destroy_cdev(c);
- mutex_unlock(&c->io_mutex);
- kfree(c);
- }
- return 0;
-}
-
-/**
- * aim_write - implements the syscall to write to the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to write
- * @offset: offset from where to start writing
- */
-static ssize_t aim_write(struct file *filp, const char __user *buf,
- size_t count, loff_t *offset)
-{
- int ret;
- size_t actual_len;
- size_t max_len;
- struct mbo *mbo = NULL;
- struct aim_channel *c = filp->private_data;
-
- mutex_lock(&c->io_mutex);
- while (c->dev && !ch_get_mbo(c, &mbo)) {
- mutex_unlock(&c->io_mutex);
-
- if ((filp->f_flags & O_NONBLOCK))
- return -EAGAIN;
- if (wait_event_interruptible(c->wq, ch_has_mbo(c) || !c->dev))
- return -ERESTARTSYS;
- mutex_lock(&c->io_mutex);
- }
-
- if (unlikely(!c->dev)) {
- ret = -EPIPE;
- goto unlock;
- }
-
- max_len = c->cfg->buffer_size;
- actual_len = min(count, max_len);
- mbo->buffer_length = actual_len;
-
- if (copy_from_user(mbo->virt_address, buf, mbo->buffer_length)) {
- ret = -EFAULT;
- goto put_mbo;
- }
-
- ret = most_submit_mbo(mbo);
- if (ret)
- goto put_mbo;
-
- mutex_unlock(&c->io_mutex);
- return actual_len;
-put_mbo:
- most_put_mbo(mbo);
-unlock:
- mutex_unlock(&c->io_mutex);
- return ret;
-}
-
-/**
- * aim_read - implements the syscall to read from the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to read
- * @offset: offset from where to start reading
- */
-static ssize_t
-aim_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
-{
- size_t to_copy, not_copied, copied;
- struct mbo *mbo;
- struct aim_channel *c = filp->private_data;
-
- mutex_lock(&c->io_mutex);
- while (c->dev && !kfifo_peek(&c->fifo, &mbo)) {
- mutex_unlock(&c->io_mutex);
- if (filp->f_flags & O_NONBLOCK)
- return -EAGAIN;
- if (wait_event_interruptible(c->wq,
- (!kfifo_is_empty(&c->fifo) ||
- (!c->dev))))
- return -ERESTARTSYS;
- mutex_lock(&c->io_mutex);
- }
-
- /* make sure we don't submit to gone devices */
- if (unlikely(!c->dev)) {
- mutex_unlock(&c->io_mutex);
- return -EIO;
- }
-
- to_copy = min_t(size_t,
- count,
- mbo->processed_length - c->mbo_offs);
-
- not_copied = copy_to_user(buf,
- mbo->virt_address + c->mbo_offs,
- to_copy);
-
- copied = to_copy - not_copied;
-
- c->mbo_offs += copied;
- if (c->mbo_offs >= mbo->processed_length) {
- kfifo_skip(&c->fifo);
- most_put_mbo(mbo);
- c->mbo_offs = 0;
- }
- mutex_unlock(&c->io_mutex);
- return copied;
-}
-
-static unsigned int aim_poll(struct file *filp, poll_table *wait)
-{
- struct aim_channel *c = filp->private_data;
- unsigned int mask = 0;
-
- poll_wait(filp, &c->wq, wait);
-
- if (c->cfg->direction == MOST_CH_RX) {
- if (!kfifo_is_empty(&c->fifo))
- mask |= POLLIN | POLLRDNORM;
- } else {
- if (ch_has_mbo(c))
- mask |= POLLOUT | POLLWRNORM;
- }
- return mask;
-}
-
-/**
- * Initialization of struct file_operations
- */
-static const struct file_operations channel_fops = {
- .owner = THIS_MODULE,
- .read = aim_read,
- .write = aim_write,
- .open = aim_open,
- .release = aim_close,
- .poll = aim_poll,
-};
-
-/**
- * aim_disconnect_channel - disconnect a channel
- * @iface: pointer to interface instance
- * @channel_id: channel index
- *
- * This frees allocated memory and removes the cdev that represents this
- * channel in user space.
- */
-static int aim_disconnect_channel(struct most_interface *iface, int channel_id)
-{
- struct aim_channel *c;
-
- if (!iface) {
- pr_info("Bad interface pointer\n");
- return -EINVAL;
- }
-
- c = get_channel(iface, channel_id);
- if (!c)
- return -ENXIO;
-
- mutex_lock(&c->io_mutex);
- spin_lock(&c->unlink);
- c->dev = NULL;
- spin_unlock(&c->unlink);
- if (c->access_ref) {
- stop_channel(c);
- wake_up_interruptible(&c->wq);
- mutex_unlock(&c->io_mutex);
- } else {
- destroy_cdev(c);
- mutex_unlock(&c->io_mutex);
- kfree(c);
- }
- return 0;
-}
-
-/**
- * aim_rx_completion - completion handler for rx channels
- * @mbo: pointer to buffer object that has completed
- *
- * This searches for the channel linked to this MBO and stores it in the local
- * fifo buffer.
- */
-static int aim_rx_completion(struct mbo *mbo)
-{
- struct aim_channel *c;
-
- if (!mbo)
- return -EINVAL;
-
- c = get_channel(mbo->ifp, mbo->hdm_channel_id);
- if (!c)
- return -ENXIO;
-
- spin_lock(&c->unlink);
- if (!c->access_ref || !c->dev) {
- spin_unlock(&c->unlink);
- return -EFAULT;
- }
- kfifo_in(&c->fifo, &mbo, 1);
- spin_unlock(&c->unlink);
-#ifdef DEBUG_MESG
- if (kfifo_is_full(&c->fifo))
- pr_info("WARN: Fifo is full\n");
-#endif
- wake_up_interruptible(&c->wq);
- return 0;
-}
-
-/**
- * aim_tx_completion - completion handler for tx channels
- * @iface: pointer to interface instance
- * @channel_id: channel index/ID
- *
- * This wakes sleeping processes in the wait-queue.
- */
-static int aim_tx_completion(struct most_interface *iface, int channel_id)
-{
- struct aim_channel *c;
-
- if (!iface) {
- pr_info("Bad interface pointer\n");
- return -EINVAL;
- }
- if ((channel_id < 0) || (channel_id >= iface->num_channels)) {
- pr_info("Channel ID out of range\n");
- return -EINVAL;
- }
-
- c = get_channel(iface, channel_id);
- if (!c)
- return -ENXIO;
- wake_up_interruptible(&c->wq);
- return 0;
-}
-
-/**
- * aim_probe - probe function of the driver module
- * @iface: pointer to interface instance
- * @channel_id: channel index/ID
- * @cfg: pointer to actual channel configuration
- * @parent: pointer to kobject (needed for sysfs hook-up)
- * @name: name of the device to be created
- *
- * This allocates achannel object and creates the device node in /dev
- *
- * Returns 0 on success or error code otherwise.
- */
-static int aim_probe(struct most_interface *iface, int channel_id,
- struct most_channel_config *cfg,
- struct kobject *parent, char *name)
-{
- struct aim_channel *c;
- unsigned long cl_flags;
- int retval;
- int current_minor;
-
- if ((!iface) || (!cfg) || (!parent) || (!name)) {
- pr_info("Probing AIM with bad arguments");
- return -EINVAL;
- }
- c = get_channel(iface, channel_id);
- if (c)
- return -EEXIST;
-
- current_minor = ida_simple_get(&minor_id, 0, 0, GFP_KERNEL);
- if (current_minor < 0)
- return current_minor;
-
- c = kzalloc(sizeof(*c), GFP_KERNEL);
- if (!c) {
- retval = -ENOMEM;
- goto error_alloc_channel;
- }
-
- c->devno = MKDEV(major, current_minor);
- cdev_init(&c->cdev, &channel_fops);
- c->cdev.owner = THIS_MODULE;
- cdev_add(&c->cdev, c->devno, 1);
- c->iface = iface;
- c->cfg = cfg;
- c->channel_id = channel_id;
- c->access_ref = 0;
- spin_lock_init(&c->unlink);
- INIT_KFIFO(c->fifo);
- retval = kfifo_alloc(&c->fifo, cfg->num_buffers, GFP_KERNEL);
- if (retval) {
- pr_info("failed to alloc channel kfifo");
- goto error_alloc_kfifo;
- }
- init_waitqueue_head(&c->wq);
- mutex_init(&c->io_mutex);
- spin_lock_irqsave(&ch_list_lock, cl_flags);
- list_add_tail(&c->list, &channel_list);
- spin_unlock_irqrestore(&ch_list_lock, cl_flags);
- c->dev = device_create(aim_class,
- NULL,
- c->devno,
- NULL,
- "%s", name);
-
- retval = IS_ERR(c->dev);
- if (retval) {
- pr_info("failed to create new device node %s\n", name);
- goto error_create_device;
- }
- kobject_uevent(&c->dev->kobj, KOBJ_ADD);
- return 0;
-
-error_create_device:
- kfifo_free(&c->fifo);
- list_del(&c->list);
-error_alloc_kfifo:
- cdev_del(&c->cdev);
- kfree(c);
-error_alloc_channel:
- ida_simple_remove(&minor_id, current_minor);
- return retval;
-}
-
-static struct most_aim cdev_aim = {
- .name = "cdev",
- .probe_channel = aim_probe,
- .disconnect_channel = aim_disconnect_channel,
- .rx_completion = aim_rx_completion,
- .tx_completion = aim_tx_completion,
-};
-
-static int __init mod_init(void)
-{
- pr_info("init()\n");
-
- INIT_LIST_HEAD(&channel_list);
- spin_lock_init(&ch_list_lock);
- ida_init(&minor_id);
-
- if (alloc_chrdev_region(&aim_devno, 0, 50, "cdev") < 0)
- return -EIO;
- major = MAJOR(aim_devno);
-
- aim_class = class_create(THIS_MODULE, "most_cdev_aim");
- if (IS_ERR(aim_class)) {
- pr_err("no udev support\n");
- goto free_cdev;
- }
-
- if (most_register_aim(&cdev_aim))
- goto dest_class;
- return 0;
-
-dest_class:
- class_destroy(aim_class);
-free_cdev:
- unregister_chrdev_region(aim_devno, 1);
- return -EIO;
-}
-
-static void __exit mod_exit(void)
-{
- struct aim_channel *c, *tmp;
-
- pr_info("exit module\n");
-
- most_deregister_aim(&cdev_aim);
-
- list_for_each_entry_safe(c, tmp, &channel_list, list) {
- destroy_cdev(c);
- kfree(c);
- }
- class_destroy(aim_class);
- unregister_chrdev_region(aim_devno, 1);
- ida_destroy(&minor_id);
-}
-
-module_init(mod_init);
-module_exit(mod_exit);
-MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("character device AIM for mostcore");
Code Review / AGL / meta-agl-demo.git / blobdiff